This invention is concerned with new members of the acidic polycyclic ether group of antibiotics, a class of compounds characterized biologically by their effect on cation transport in mitochondria. This family of antibiotics includes monensin (J. Amer. Chem. Soc., 89:5737, 1967); nigericin (Biochem. Biophys. Pes. Comm. 33:29, 1968); grisorixin (J. Chem. Soc. Chem. Commun., 1421, 1970); dianemycin (J. Antibiotics, 22:161, 1969); salinomycin (J. Antibiotics, 27:814, 1974); X-537A (J. Chem. Soc. Chem. Commun., 967, 1972); X-206 (J. Chem. Soc. Chem. Commun., 927, 1971); and A204A (J. Amer. Chem. Soc., 95:3399 1973).
The polycyclic ether antibiotics listed above are active against Gram-positive bacteria, fungi and protozoa. These antibiotics exhibit potent anticoccidial activity.
The control of coccidiosis continues to be a serious problem to the poultry industry. There are six species of coccidia which produce easily discernible morbidity in susceptible chickens. Eimeria tenella, E. necatrix, E. brunetti, E. acervulina, E. maxima and E. mivati produce damage either directly through destruction of epithelial cells of the digestive tract or indirectly through production of toxins. Three other species of protozoa belonging to the same genus are considered to be relatively inocuous; however, E. mitis, E. hagani and E. praecox are capable of reducing weight gain, lowering feed efficiency and adversely affecting egg production.
The polycyclic ether antibiotics possess a high degree of effectiveness against all species of Eimeria. These antibiotics can, therefore, be regarded as "broad spectrum" coccidiostats.